Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936469AbcJVIlx (ORCPT ); Sat, 22 Oct 2016 04:41:53 -0400 Received: from mail-wm0-f42.google.com ([74.125.82.42]:36590 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbcJVIlf (ORCPT ); Sat, 22 Oct 2016 04:41:35 -0400 Date: Sat, 22 Oct 2016 10:41:31 +0200 From: Daniel Vetter To: Chris Wilson , Takashi Iwai , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Noralf =?iso-8859-1?Q?Tr=F8nnes?= , David Airlie Subject: Re: [PATCH] drm/fb-helper: Don't call dirty callback for untouched clips Message-ID: <20161022084131.GQ20761@phenom.ffwll.local> Mail-Followup-To: Chris Wilson , Takashi Iwai , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Noralf =?iso-8859-1?Q?Tr=F8nnes?= , David Airlie References: <20161020143952.2538-1-tiwai@suse.de> <20161020145604.GW4329@intel.com> <20161021123032.GZ20761@phenom.ffwll.local> <20161021125728.GL25629@nuc-i3427.alporthouse.com> <20161021181903.GN20761@phenom.ffwll.local> <20161021200227.GU25629@nuc-i3427.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161021200227.GU25629@nuc-i3427.alporthouse.com> X-Operating-System: Linux phenom 4.6.0-1-amd64 User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1001 Lines: 23 On Fri, Oct 21, 2016 at 09:02:27PM +0100, Chris Wilson wrote: > On Fri, Oct 21, 2016 at 08:19:03PM +0200, Daniel Vetter wrote: > > On Fri, Oct 21, 2016 at 01:57:28PM +0100, Chris Wilson wrote: > > > I think of a use for sending an empty clip: where you don't want to > > > push any new pixel data, but you do want to be sure that the pipeline > > > has been flushed. > > > > What exactly should an empty rectangle flush out? It's a bit unclear, but > > for speed I guess drivers should be allowed to make dirty async ... > > No idea! I'm just speculating that I can see a use for a dirtyfb barrier > even with an empty cliprect. Empty clips are a useful distinction > elsewhere that I would suggest not forbidding them outright but defining > their behaviour. In general I prefer clarifying unused and undefined cases to "reject them". We can always add a cap later on when we want to give them some real meaning. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch